Compressor



Nov. 23, 1-937. F. M. MO'CRACKEN COMPRES SOB 3 Sheets-Sheet l INVENTOR.FRED M. MCCRACKEN. W 7

ATTORNEY.

Filed May 29, 1933 l a 4A A6 fi ll Z5 Nov. 23, 1937.

4, 11 1 2 N E w R w R CE m m .C M F Filed May 29, 1955 5 Sheets-Sheet 2INVENTOR.

Fazo M. McCRAcKEN,

' Nov. 23, 1937.

F. M. MCCRACKEN COMPRESSOR Filed May 29, 1955 3 Sheets-Sheet 3 INVENTOR.

FRED M. McCRAcKaNs Patented Nov. 23, 1937 PATENT OFFICE 1 2,100,014COMPRESSOR Fred M. McCracken, Norwood, Ohio Application May 29, 1933,Serial No. 673,393

10 Claims.

This invention relates to compressors in general. but more'particularlyto a compressor suitable for compressing a chemical gas such as used indomestic and other. refrigerating devices but it will beunderstood thatit may be used for other compression purposes as well.

Heretofore, two different'principles of com-- pressors have generallybeen used for this pura ing the's'eal confining the gas.

' pose-the reciprocating piston type and the rotary type. The pistontype of compressor has usually been driven by a belt from a powerdevice, such as an electric motor, and this arrangement enabled the useof a fan on the motor shaft to provide a, forced draft for cooling thecondenser of the refrigeration device but it made necessary the use of ashaft seal around the shaft of the compressor to prevent escape of thegas from within. Such seals have invariably given considerable troubleand proven very unreliable. Other piston types 'of compressors have beendirectly connected to the motor and both motor and compressorhermetically sealed in a container .withthe gas thus obviating therequirement fora shaft seal but this arrangem'ent did not; permit of theuse'of a fan draft I for cooling thecondenser, and it had the addeddisadvantagejthat themotor could not be serviced w'ithout-"unsealing thecontainer and thereby liberating the 'gas. The rotary type ofcompressor, being usually directly connected to the motor, was notfavorable'to the use of a shaft seal because of the high speed of theshaft and therefore this type of compressor, together'with the motorcould not be serviced without destroy- Another disadvantage of both thepiston type and the rotary type of compressor is that an enormous amountof power is wasted in overcoming the friction of the moving parts evenwith the best of workmanship and good lubrication and in the piston typeof compressor there is an additional Waste of powerdue to starting andstopping the recipro'cating parts at each end of their stroke whichoccurs many hundreds of times per minute. Furthermore, frictioninevitably results in wear onthe parts and consequent loss'of efficiencyin' compression thus making service and replacement of parts frequentlynecessary in order to maintain satisfactory performance, and the expenseincident thereto greatly increases the cost of electric refrigeration tothe user or places a serious burden on the manufacturer or dealer.."On'e object of this invention therefore is to provide a compressorthat is devoid of any reciproc'ating parts, such as pistons orcylinders.

or of any revolving parts, such as the eccentrics, rollers or bladescommon to rotary types of compressors thereby eliminating the frictionand resultant wear incident thereto, conserving pow-1 er and effectingreal economy in operating and maintenance expense.

Another object is to provide a compressor which can be hermeticallysealed independent of the power device thus having the shaft of thepower device available for the application of a fan to provide a forceddraft for cooling a condenser and also thus avoiding the use of a shaftseal so that the power device may be readily replaced or servicedwithout liberating any of the refrigerating gas.

Another object is to provide a compressor that can be directly connectedto the actuating member of a power device (such as the shaft of anelectric motor) without the use of a clutch, coupling or any tied-upconnection.

Another object is to provide a compressor having only one majorpower-actuated element directly adapted to effect compression of thegas,

thus, making for simplicity and low cost of mancompact form yet easilyassembled and the parts thereof readily accessible for examination orreplacement.

Another object is to obtain a higher degree of volumetric efiiciencythan that which is possible with other types of compressors. I These andother objects will be apparent from the following description and theaccompanying drawings which illustrate a preferred form of theinvention. 0 My invention will be further readily understood from thefollowing description and claims and from the drawings, in which latter:

Fig. l is an externalside elevation of the compressor unit and theattached power device.

Fig. 2 is an end elevation of the same as viewed from the compressorend.

Fig. 3 is a sectional elevation through the compressor unit takensubstantially-on a line 3-3 of Fig.2. 0

Fig. 4 is a sectional of Fig. 3. Fig. 5 is a sectional view taken on aline 5-5 of F g, 3.

Fig. 6 is a sectional view taken on the line 6-6 of Fig. 3.

Fig. '7 is a sectional view taken on a line 1-1 of Fig. 3.

Figs. 8, 9 and 10 are comparative views to Fig. 4 and show the relativepositions of the compression elements at different stages of the cycleof movement.

Fig. 11 is a profile view of the discharge valve disc.

Fig. 12 is a perspective view of the blade or division bar.

Fig. 13 is a longitudinal section of a modified form of compressor unit.

Fig. 14 is 'a sectional view'taken on a line |4|4 of Fig. 13.

Figs. 15, 16 and 1'7 are sectional views taken on the line ||5 of Fig.13, and, in connection with Fig. 14, show the relative positions of thecompression elements at different stages of the cycle of movement.

In the drawings, 20 represents'a compressor housing having a portion 2|arranged for attachment to any suitable structure by means of bolts orotherwise.

The body portion of the'housing 20 is preferably of cylindric form andrigidly attached to one end thereof is a cap'or head plate 22 which issecured by means of screws 23. The cap plate 22 not only serves as aclosure for that end of the housing but also as one of the side platesfor the compression chamber 24 and as a mounting plate for the cylinder25 and the other side plate 26 which are secured to the plate 22 bymeans of the screws 27. This assembly consisting of the cylinder 25 andthe plates 22 and 26 may be termed the cylinder unit and in order thatthe annular location thereof relative to the housing 20 maybeestablishedwith precision, the said housing is bored out to anaccurate diameter and the cylinder 25 is accurately positioned thereinconcentric to the outside diameter so that .the axis thereof coincideswith the axis of the bore in the housing.

Positioned within the cylinder 25 and laterally confined between theplates 22 and 26 is a movable member 28 of cylindric form which. in theabsence of a more appropriate term, may be called the eccentric merelybecause it is normally positioned and held eccentrically within thecylinder, that is, the axis of the eccentric is spaced from the axis ofthe cylinder 25 a distance equal to exactly one half the differencebetween the diameter of the cylinder bore and the-diameter of theeccentric so that the peripheral surface of the eccentric isthus incontact with the wall of the cylinder.

The eccentric 28 is provided with a hub-like portion 29 concentricthereto which extends laterally through an opening concentricallylocated in the plate 26 and comprises a flange 3| and a threaded tenon32. The eccentric 28 is further provided with a detachable cup-likeextension 33 which is concentrically mounted on the tenon 32 and heldsecurely against the face of the flange 3| by a jam nut 34. Theextension 33 has a flange 35 to which is rigidly secured one endof acylindric metal bellows or -sylphon 36 which has its other end similarly.attached to the plate 26. Thus'there is provided a gas-tight connectionof conduit form, axially flexible but torsionally rigid, between thecylinder 25 which is stationary and the eccentric 28 which is movable.

Attached to the housing 20 at the end thereof opposite the cylinderunit, is a power device 3?.

here shown as an electric motor having a rotary shaft 38 and bearingcaps 38 and 40 which support said shaft.

In order that the annular location and alignment of the shaft 38relative to the cylinder 25 may be established with precision, thehousing 20, at the motor end, is bored out to an accurate diameter andexactly concentric with the bore at the other end which positionsthecylinder and the cap 40 is provided with a flange 4| which isaccurately machined for a snug fit in the housing and exactly concentricto the bore of the bearing member 42 secured in the cap 46 forsupporting the shaft 38. Thus the axis of the said shaft is establishedexactly concentric and in alignment with the axis of the cylinder 25.The motor 31 is secured to the housing 20 by the screws 43 which extendthrough ears 4% on the housing and are threaded into the cap 49.

The shaft 38 is so arranged that the rotation thereof will causemovement of the eccentric" 28-not rotary movement because the saideccentric is restrained from any rotary movement by its connection tothe plate 26 through the bellows 36 but the movement is'a gyratorymovement of the eccentrics" axis around the axis of ference between thediameter of the bore in the cylinder and the diameter of the eccentric28 so as to hold the eccentric 28 eccentrically within the said bore tosuch an extent that the peripheral surface of the eccentric 28' is incontact with the wall of the cylinder, as previously referred to. Thus,as the shaft 38 rotates, the eccentric 28 is caused to walk-aroundwithin the bore of the cylinder 25, always in peripheral contact withthe wall of the cylinder and held in constant peripheral relationthereto by the torsionally rigid sylphon 36.

In order to utilize this movement for compressing a vapor or gas, thereis provided a blade or division .bar 46 which is preferably confined ina radial slot 41 in the eccentric 28 and yieldingly held into contactwith the wall of the cylinder 25 by compression springs 48, the saidblade being angularly located intermediate an intake port 49 in theeccentric 28 and a discharge valve 56 in the cylinder 25 thus serving asa wall to separate the intake from the discharge port. By thisarrangement, gas enters the chamber 24 on one side of the blade 46through the port 49 and is discharged therefrom on the other side of theblade through the valve 58 which comprises a 'port-hole 5| normallyclosed by a disc 52 under the influence of a compression spring 53 whichis located in a chamber'54 and confined between the said disc and aretaining screw 55 mounted in the cylinder 25. The force of thecompressed it in correct position.

blade 46, that is, when substantially half a charge of gas has beentaken into the chamber on one side of the blade and compression on theother side has been half accomplished. When the eccentric is in thisposition, the point of contact between the said eccentric and the wallof the cylinder is opposite the blade H6 on a. direct line through thecenter of the blade and the axis of the said eccentric and the axis ofthe cylinder 25 is also on said line intermediate the blade and theeccentrics axis.

Figs. 8, 9 and 10 show the position of the eccentric 28 at differentstages in its cycle of movement. For example: When the shaft has rotatedclockwise substantially 90 degrees from the position shownein Fig. 5,the axis of the said eccentric has thus been moved .90 degrees clockwisearound the axis of the cylinder 25 to the position shown in Fig. 8resulting in nearly full accomplishment of compression and discharge onthat side of the blade and almost a full charge of gas in the chamber onthe intake side of the blade.

A further 90 degree movement of the shaft 3% brings the eccentric intothe position shown in Fig. 9 wherein compression has been fullyaccomplished and the chamber 2% supplied with a full charge of gascompression of which is about to begin on the discharge side and a newcharge about to be taken in on the intake side.

-A-still further 90 degree rotation of the shaft 38 will result inpositioning the eccentric as shown in Fig. 10 wherein partialcompression has taken place on the discharge side and a partial chargeof gas taken in on the intake side.

The complete cycle of movement of the eccentric 28 will have beenaccomplished with a further 90 degrees of rotation of the shaft 38resulting in the said eccentric again occupying the position shown inFig.5. Each rotation of the shaft 33 will thus effect one complete cycleof movement of the eccentric 28, that is, one full planetary circuit ofthe said eccentrics axis around the axis of the cylinder 25, resultingin one full charge of gas being compressed and discharged and anotherfull charge being taken in.

In order that gas may be conducted from the cooling element of arefrigerator (when the device, is thus applied), or from any othersource, to the intake port 49 of the compressor, the plate 22 may beprovided with a suitable fitting such as 51 which is arranged forconnection with said cooling element by tubing or otherwise. Openings5B, 59 and 60 arranged respectively in plate 22, cylinder 25 and plate26 provide a passagewayfor the gas from the fitting 51 into the chamberwithin the bellows 36 from whence it may pass to the intake port d9through an opening 6I which extends longitudinally through theeccentric'28 from the flange 3i to the face adjacent the'plate 22. Theintake port M is shown as comprising a channel recess in the side faceof the eccentric 28 and may, if desired, be arranged in duplicate, oneport on each side of the eccentric as shown.

Transit of the compressed gas from the discharge valve 50 may beprovided for by a passageway comprising openings 62 and 63arrangedrespectively in cylinder 25 and plate 22, the opening 62communicating with the valve chamber 54 and opening 63 with a suitablefitting such as 6A which is arranged for connection, by tubing or otherwise with the condenser of a refrigerator or other device.

In order to provide ample lubrication for the bearing of the eccentric28 on the shaft extension 45 and also for the bearing c2 of the shaft38,

the chamber within the housing 20 may contain oil in sufficient quantityto immerse both bearings, in which case the cap M is provided with asuitable oil retainer or seal 65 to prevent escape of oil around theshaft into the motor.

Inasmuch as an induced draft of circulating air is advantageous forradiating generated heat from the motor and compressor and as a forceddraft is practically necessary for efficient cooling of the condensercoil, the free end of the motor shaft 38 is provided with a fan 66 toserve this purpose.

The modified form of the compressor unit shown in Figs. 13 to 1'7inclusive embodies the same basic idea hereinbefore described andperforms the function of compression in a manner which accomplishessimilar results. The practical difference herein resides principally inthe reversal of the primary elements-the cylinder being movable and theeccentric being stationary.

In this instance, lil represents the compressor housing having a portionii for mounting purposes. Rigidly attached to one end of the housing isa supporting cap i2 which is snugly fitted into a bore in the housingand secured by means of screws 73. The cap 12 is provided with anextension M to support the eccentric i5 which is of cyiindric form andcomprises a portion it having an extension Ti by which the saideccentrio is supported and securely held in the bore 78 in the capextension M thus positioning the said eccentric exactly concentric tothe bore in the housing '70. e

The cylinder unit, comprises the cylinder Iii and side plates 80 and tiwhich enclose the compression chamber 82 and which are secured togetherby screws 83. Rigidly secured to plate fl is one end of a cylindricmetal bellows M which has its other end similarly attached to the cap52. Thus there is provided a gas-tight connection of conduit form,axially flexible but torsionaliy rigid between the eccentric it which isstationary and the cylinder it which is movable.

The motor cap 85 is mounted on the end of the housing Iii and carriesabearing 86 which supports the motor shaft t'l.

In order that the annular location and alignment of the shaft tlrelative to the eccentric l5 may be established with precision, thehousing in at the motor end is bored out to an accurate diameter andexactly concentric with the bore at the other endwhich positions theeccentric and the cap 85 is provided with a flange 88 which isaccurately machined for a snug fit in the housing and exactly concentricto the bore of the bearing member 86. Thus the axis of the shaft 81 isestablished exactly concentric and in alignment with the axis of theeccentric F5. The motor can 85 is secured to the housing iii by thescrews 89 which extend through ears W on the housing and are threadedinto the cap.

' extension 9! of the shaft Bl said extension being eccentric to theaxis of the'said shaft in amount sufficient to hold the cylinder 79eccentric to the eccentric 15 to such an extent that the peripheralsurface of the said eccentric is in contact with the wall of the saidcylinder. Thus, as the shaft 81 rotates, the cylinder unit" is caused towalkaround the eccentric 15 always maintaining peripheral contactbetween the said eccentric and the wall of the cylinder and held inconstant peripheral relation thereto by the torsionally rigid sylphon84.

In this instancefthe blade or division bar 92 is shown as being confinedin a radial slot 93 in the cylinder 19 and yieldingly held into contactwith the eccentric by compression springs 94, the point of contact beingsubstantially midway between the intake port 95 and discharge valve 96both of which are positioned in the eccentric 15. By this arrangement,the gas enters the chamber 82 on one side of the blade 92 through theport 95 and is discharged therefrom on the other side of the bladethrough the valve 96 which comprises a port-hole 91 normally closed by adisc 98 under the influence of a compression spring 99 which is locatedin a chamber I and confined between the said disc and the bottom wall ofthe said chamber. The port-hole 91 is embodied in a disc IM which issecurely held in a recess in the eccentric 15. The force of thecompression acting upon that portion of the surface of the disc 98 whichis exposed thereto through the port-hole 91 causes the said disc to moveagainst the action of the spring 99 and thus permit the compressed gasto pass through the said port-hole into the chamber l00. So that themovement of the disc 98 may be limited to a desirable extent, thechamber I00 is formed I with a central stem I82 of proper length andthis a'.;o serves as a pilot for the spring 99 to define its position.

In order that gas may be conducted from an external source to the intakeport 95, the cap 12 -may be provided with a suitable fitting E03 fortube connection and an opening 194 in the said cap may provide apassageway for the gas from the said fitting into the chamber within thebellows 84 from whence it may pass to the of the eccentric.

Transit of the compressed gas from the valve 96 may be provided for by apassageway E06 extending radially through the eccentric 15 and'communicating at its outer end with the chamber 590 through an opening901 in the wall of the stem Hi2 and at its inner end with a passageway9% extending longitudinally through the eccentric 15 to the bore 18 andthence through an opening its to a suitable fitting i 10 mounted in thecap 12 and arranged for tubing connection with the device to be served.

Figs. 14, l5, l6 and 17 show the position of the cylinder is atdifferent stages in its cycle of movement. Fig. 14 shows the positionwhen half a chargeoi gas has been taken into the chamber on one side ofthe blade and compression on the other side has been half accomplished.Fig. 15 shows the position when the shaft 81 has rotated clockwise 90degrees from the position shown in Fig. 14 thus moving the axis of thecylinder iii an equivalent amount around the axis of-the eccentric15.Fig. 16 shows the position after an additional 90 degrees of movementand Fig. 17 shows a still further movement of 90 degrees. It will thusbe seen that a complete rotation of the shaft 81 will effect a completecycle of movement of the cylinder 19, that is, one full planetarycircuit of the cylinders axis around the axis of the eccentric 15,resulting in one full charge of gas being compressed and another fullcharge being taken in.

Ample lubrication for the bearing of the plate 88 on theshaft extension9| and also for the shaft bearing 86 may be provided for by charging thehousing 10 with, suflicient quantity of lubricating oil to immerse bothbearings. To prevent escape of any of such oil around the shaft into themotor, the cap 85 may be provided with a suitable oil seal Ill.

From the foregoing, it will be apparent that I have provided acompressor which accomplishes, in a novel and practical manner, all ofthe objectives stated herein.

It is to be understood that the disclosure made. herein is a preferredform and that the various elements of the device may be modified to suitparticular requirements without departing from the spirit and scope ofthe invention as set forth in the following claims.

Having thus fully described my invention what I claim as new and desireto secure by Letters Patent, is:

LA compression device comprising a member having a cylindric chamber, acylindric member enclosed within said chamber and disposed ec-,

centric thereto, an intake port in one of said members, a discharge portin one of said members, ablade movably mounted in one of said members,yieldingly held into peripheral contact with the other of said membersand positioned radially intermediate said ports, said members thusfunctioning as a pump when one member is held stationary and the othermember is given a gyratory motion relative thereto, sealed connectingmeans between said members comprising a vapor-tight flexible tubearranged so that the chamber therewithin receives leakage of vapor fromthe compression chamber of said pump thus preventing escape thereof tothe atmosphere, and a device to actuate said other member in a gyratorymanner.

2. A compression device comprising a stationary'cylindric member, amovable cylindric memher, one of said members encompassing the other andarranged with its axis parallel to the axis of said other member butdisplaced relative thereto, an intake port in one of said members, adischarge port in one of said members, a blade movably mounted in one ofsaid members, yieldingly held into peripheral contact with the other ofsaid members and positioned radially intermediate said ports, saidmembers thus functioning as a pump when said movable member is given agyratory movement, a vapor-tight flexible tubu .lar structure attachedatone end to said stationtion to said chamber, one of said walls having anaperture located axially therein and said cylindric member having anaxially disposed extension projecting through said aperture andterminating in a portion remotely spaced from said apertured' wall, oneof said members being stationary and the other being arranged forgyratory movement relative thereto whereby vapor may be compressedwithin said chamber, a vapor-tight flexible tubular structureencompassing said extension and having one end hermetically connected tosaid remote portion thereof and having manner.

4. In a gyratory compressor, the combination with a cylinder member andan eccentric member, one of which is stationary and the other movable ina gyratory manner, of a vapor-tight flexible tubular structure havingone end hermetically connected to said stationary member and the otherend hermetically connected to said movable member, said structure actingto prevent rotation of said movable member about its axis withoutrestricting its freedom to gyrate and being arranged in relation to saidmembers so as to receive within said tubular structure leakage of vaporfrom the compression chamber of said compressor and thus serve as a sealto prevent escape. of said vapor to the atmosphere.

5. The combination with a gyratory compressor mechanism comprising acylinder member provided with end walls and an eccentric member confinedtherebetween, of hermetically attached connecting means joining saidcylinder member to said eccentric member, said means comprising avapor-tight flexible tubular structure arranged in relation to said.members so that compressed vapor escaping between said eccentric memberand the surface of the end wall adjacent to said structure will beconfined by and within said structure which thus serves as a seal toprevent escape of said vapor to the atmosphere.

6. Means for sealing a gyratory compression mechanism comprising acylinder element and an eccentric element confined therewithin, whichconsists in the provision of a vapor-tight tubular structure, axiallyflexible but torsionally non-flexible, said structure being hermeticallyconnected at one end to said cylinder element and hermetically connectedat its other end to said eccentric element, and being arranged inrelation to said elements so that the chamber within said struc turewill receive leakage of vapor from the compression chamber of saidcompression mechanism and thus said vapor will be confined by and withinsaid structure so that it may be available for redelivery to the saidcompression chamber.

7. In a gyratory compressor mechanism wherein vapor is compressed withina cylinder element by an eccentric element as a result of gyratorymotion of one of said elements, thecombination of an intake passagewaymap be conducted to the compression chamber within said cylinderelement, and hermetically sealed connecting means joining said cylinderelement to said eccentric element, said means comprising a flexibletubular structure arranged in relation to said elements so that leakageof vapor from said compression chamber will be received by and withinsaid tubular structure, said tubular structure having communication withsaid passageway whereby said leakage may be returned to said compressionchamber.

8. In a gyratory compressor mechanism wherein vapor is compressed withina cylinder element by an eccentric element as a result of gyratorymotion of one of said elements, an intake passageway through which vapormay be conducted to the compression chamber within said cylinderelement, said passageway comprising a flexible tubular structure havingone end hermetically connected to said cylinder element and the otherend hermetically connected to said eccentric element, said tubularstructure being arranged in relation to said elements so that leakage ofvapor from said compression chamber will be received within saidpassageway so that said leakage may be returned to said compressionchamber.

9, Means for sealing a gyratory compression mechanism comprising acylinder element having a compressor chamber and an eccentric elementconfined therewithin, which consists in the pro vision of connectingmeans between said elements comprising a vapor-tight axially flexiblebut torsionally rigid tubular structure and a fully rigid cylindricstructure, one of said structures freely encompassing the other, saidcylindric structure being hermetically connected at one end to one ofsaid elements and similarly connected at its other end to one end ofsaid tubular structure, the other end of said tubular structure beinghermetically connected to the other of said elements, said structuresbeing arranged in relation to said elements so that the free spacebetween said structures will receive leakage of vapor from thecompression chamber of said compression mechanism and thus said vaporwill be confined by and within said connecting means so that it may beavailable for redelivery to the said compression chamber.

10. The combination with a gyratory compressor mechanism comprising acylinder member provided with end walls and an eccentric member confinedtherebetween, of hermetically attached cylindric connecting meansjoining said cylinder member to said eccentric member, said meanscomprising a vapor-tight flexible tubular structure and being arrangedin relation to said members so that compressed vapor escaping betweensaid eccentric member and the surface of the end wall adjacent to saidconnecting means will be confined by and within said means which thusserves as a seal to prevent escape of said vapor to the; atmosphere.

through which vapor

